Alternating-current local circuits for code-signaling telegraphs



Mar. 27, 1923. 1,449,984.

I J. I. GHEGAN.

ALTERNATING CURRENT LOCAL CIRCUITS FOR CODE SIGNALING TELEGRAPHS.

FILED APR- 8.1919.

INVENTOR 4 4M 4 W L BY 2 5 ATTORNEY Patented Mar. 27, 1923.

JOHN OSEPH GHEGAN, OF EAST ORANGE, NEW JERSEY.

ALTERNATING-CULRENT LOCAL CIRCUITS FOR CODE-SIGNALING TELEGRAPHS Application filed April 8, 1919. Serial No. 288,471.

'1 all whom it may concern Be it known that I, JOHN J osnPH GnncAn, a citizen of the United States, reslding 1n East Orange, Essex County, New Jersey, 3 have made .certain new and useful Improvements in Alternating-Current Local Circuits for Code-Signaling Telegraphs. In prior granted Patents N0. 1,27 5,902 and No. 1,275,903, dated August 13, 1918, I have described and claimed a local circuit for a sounder, operated by alternating current, controlled by a manually operated key, or an automatic transmitter, either w1th or without an intermediate relay or repeating points.

It has been found that when the sounder lever movement is limited to a short stroke or excursion, there is a variation in the strength or force of the impacts, due to asurging in the sounder circuit, probably an out-of-phase condition of current and voltage; and the object of this improvement is to eliminate this surging and the varying force of the stroke or impact of the sounder 5 bar upon its down stop.

For the purpose of obviating the difficulty indicated, a resistance, preferably a noninductive resistance, and a capacity are electrically connected with the sounder circuit,

and this resistance and capacity are so adjusted that the inductance due to the sounder coils, the extra resistance described and the capacity conspire to accomplish the desired result by eliminating the surglng or out-ofphase condition referred to.

The accompanying drawing illustrates the invention.

Figure 1 shows an alternating-current circuit, a simple Morse telegraph circuit, and a local, sounder circuit taking current from ihe first-named circuit; there is a resistance and a capacity bridging it, and Fig. 2 shows the same arrangement, substantially, but the capacity is in series with the resistance in the local circuit.

The circuit, a, is a commercial circuit, supplying alternating current; the simple Morse circuit, m, includes a battery, 00, a hand-operated key, or transmitter, t, and a relay, 40, operating break-points, 19, 20, in circuit 2, 3, 4, including the coils of sounder s. Sounder s has a soft iron, laminated core and pole-pieces, 30, 31; a vertically reciprocating bar, 12, is pivoted to a support, 22, fixed on the metal sounding board, 23, as is the anvil, 24; the anvil 24 carries an adjustable back stop, 10, and the bar 12 carries a down stop, 11; the spring 13' normally holds a pivoted bar, 12, on its back stop, bar 12 reciprocates or vibrates between up or back stop 10, and down stop 11, fixed on anvil 24. I

When the local circuit isheld closed, by closing key It, the armature of sounder s strikes or makes impact on its down stop and then floats at the point of maximum magnetic density in the magnetic field; that is, when circuit is closed at t, it is closed at relay contacts 19, 20, and armature of sounder s impacts and then floats between pole pieces 31, 32, Fig. 2. When circuit 2, 3, 4, is open, spring 13 of sounders holds bar 12 on its back stop 10, all as described in my prior granted patents.

The surging is entirely eliminated and avoided by including in circuit 2, 3, 4, a suitable resistance r, bridged by a capacity or condenser, 0. By properly adjusting this resistance and capacity with respect to each other and to the resistance of sounder s, the.

down stroke or impact of bar 12 is firm, uniform and resonant.

The values of resistance and capacity may be varied to satisfy operating conditions, and as a general rule a sounder coil wound to a resistance of 500 ohms and a capacity of two and one-half microfarads, bridged by a resistance of 3500 ohms, has been found to give satisfactory results. It is preferred to use an external resistance of a non-inductive type, whether bridging resistance or series resistance be employed. A carbon rod and a sliding contact form of resistance has been used with success by the applicant.

In Fig. 2 resistance 1- is shown in series with capacity. 0, but otherwise the same as in Fig. 1. The amount of resistance 1' in the arrangement shown in Fig. 2 is less than that shown in the arrangement of Fig. 1.

I found, in practice, that the floating armature eliminates chattering and that the condenser or condenser and resistance smoothes out the current so that blows of uniform strength may be made by the sounder. If the condenser or condenser and resistance are not employed the blows are not uniform owing to the voltage and current getting in and out of phase.

What I claim is A code signaling telegraph circuit including the coils of a receiving relay, and a circuit changing armature contact operated by said relay coil, in combination with a local circuit, including a source of alternating current supply and the coils of a sounder, with a capaclty and a resistance in series with said sounder coil.

JOHN JOSEPH GHEGAN. 

